Left channel
Wired incorrectly see attached schematic
What the picture shows was the error wiring I understand. Am I right?
You have E283CC in Siemens only or other also like Mullard Philips Valvo?Better.
7N7 are running to circa 6mA, could I push up to 9mA? if yes what resistors have I to change?
They are running "by the book" as marked on the V1.2 schematic. But if you are curious for more mA I will have to check later for values because I don't have my design notes in this computer.
Only Siemens bought a lot of years ago to Erno Borbely.
Maybe he hand picked low noise tubes?
7N7 are running to circa 6mA, could I push up to 9mA? if yes what resistors have I to change?
Try yourself out by parallelling 330 bias resistors. 2k, 1k... but dont push it to much over max plate dissipation 2,5 w.
For sure. All tubes bought to Erno are super high quality, I have a pair ECC88 6922 Russian that sounds superb also I have two ECC81 EI long anode very good.
Tubes in low noise high gain circuits differ sometimes a lot by sample for performance. Takes expert picking even among best suitable types for sure.
Try yourself out by parallelling 330 bias resistors. 2k, 1k... but dont push it to much over max plate dissipation 2,5 w.
But what about R12? Its in the system and it will squeeze voltage allowance across sections as the mA go up. Need to progressively go lower to allow the same voltage as before.
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